36 Transfusion medicine

Question 1

What is a unit of RBC?

How is it prepared? (4)

Answer 1

Concentrated red blood cells.

Plasma removed and replaced with glucose, electrolytes and adenine.

Question 2

How is a unit of RBC stored?

Answer 2

4 degrees for up to 35 days.

Question 3

How is a unit of RBC administered?

Answer 3

Over 1.5-3 hours.

4 hour time limit from cold removal and end of transfusion.

Question 4

What is the transfusion threshold?

Answer 4

Lowest threshold of haemoglobin not associated with symptoms of anaemia.

Question 5

How does the body adapt to anaemia? (6).

Answer 5

Increased cardiac output.
Increased coronary artery flow.
Increased oxygen extraction.
Increased 2,3-DPG levels.
Increased EPO production.
Increased erythropoiesis.

Question 6

What does tissue oxygenation depend on?

Answer 6

Concentration of haemoglobin.

Question 7

What is the trigger for blood transfusions in anaemia?

Answer 7

Less than 70g/L with mild symptoms.

Less than 80g/L with CV disease.

Question 8

When should blood transfusion take place in anaemia from acute blood loss?

Answer 8

More than 30% of blood volume or more than 1500mL lost.

Question 9

What is the aim of blood transfusion in chronic ischaemia due to myeloid failure? (3)

Answer 9

Symptomatic relief.
Improvement in quality of life.
Prevention of ischaemic organ damage.

Question 10

What is the aim of blood transfusion in chronic ischaemia due to inherited anaemia?

Answer 10

Suppression of endogenous erythropoiesis.

Target: 100-120 g/L.

Question 11

How are platelets stored and used?

Answer 11

Room temperature for 5 days from collection.

Transfusion over 30 minutes.

Question 12

When should platelets be transfused?

Answer 12

Treat bleed due to severe thrombocytopenia or platelet dysfunction.
Prevention of bleeding.

Question 13

What are the contra-indications for platelet transfusion?

Answer 13

Heparin indued thrombocytopenia and thrombosis.

Thrombotic thrombocytopenia purpura.

Question 14

How is fresh frozen plasma stored and administered?

Answer 14

-30 degrees for up to 24 months.

Thawed before used, transfused over 30 minutes.

Question 15

When should fresh frozen plasma be transfused? (3)

Answer 15

Coagulopathy with bleed/surgery.
Thrombotic thrombocytopenia purpura.
Massive haemorrhage.

Question 16

What is the treatment for life-threatening bleeding in Warfarin overdose?

Answer 16

Prothrombin complex concentrate.

Plasma-derived Vit K dependent factors: II VII IX X.

Question 17

When should CMV negative blood products be used?

Answer 17

Children under 1
Intrauterine tranfusion
Congenital immunodeficiency
Pregnant women (unless known +ve)

Question 18

When should irradiated blood products be used? (5)

Answer 18

Intrauterine transfusions.
Congenital immunodeficiency.
Hodgkin Lymphoma.
Stem cell / marrow transplant patients.
After purine analogue chemo.

Question 19

What is the pathogenesis of acute haemolytic reaction-ABO incompatibility? (4)

Answer 19

Deposition of Hb in renal tubules causes renal failure.
Stimulation of cytokine storm.
Microvascular thrombosis.
Generalised vasoconstriction mediated by NO.

Question 20

What is group and screen?

Answer 20

ABO and Rh group identification.

Screening for other major blood group antigens.

Question 21

What is cross-matching?

Answer 21

Donor selected with correct ABO, Rh and antibodies.

Some of donor and patient blood mixed to see if reaction occurs.

Question 22

What are the immunological acute transfusion reactions? (3).

Answer 22

ABO incompatibility.
Allergic reaction.
TRALI (transfusion related acute lung injury).

Question 23

What are the non-immunological acute transfusion reactions? (3).

Answer 23

TACO (transfusion associated circulatory overload).
Bacterial contamination.
Febrile non-haemolytic transfusion reaction.

Question 24

What are the delayed transfusion reactions?.
2 immunological.
1 non immunological.

Answer 24

Transfusion associated graft vs host disease. Post transfusion purpura.
Transfusion transmitted infection (viral/prion).

Question 25

Which risk is great: transfusion transmitted infection or the wrong blood product being given?

Answer 25

Wrong blood product.

Question 26

What are the symptoms of acute haemolytic reaction ABO incompatibility? (7)

Answer 26

More severe within 15mins.
Fever
Back, chest, and infusion pain 
Hypotension /shock
Hemoglobinuria
Increased bleeding (DIC)
Sense of “impending death”

Question 27

What is the pathogenesis of delayed haemolytic reaction?

Answer 27

Antigens form after transfusion toe RBC antibodies that aren’t ABO.

Question 28

When does a delayed haemolytic reaction present?
Symptoms? (3)
Bloods? (3)

Answer 28

3-14 days post transfusion.
Fatigue, jaundice, ± fever.
Drop in Hb. Increased LDH and indirect bilirubin.

Question 29

What is Coomb’s test?

Answer 29

Anti-human globulin test.

Test for incomplete IgG antibodies.

Question 30

What is transfusion related lung injury?

How does it occur?

Answer 30

Acute lung injury within 6hrs of transfusion.

Donor antibodies to recipient leukocytes - activated WBC lodge in capillaries + damage them.

Question 31

What is acute lung injury?

Answer 31

Hyperaemia.
New bilateral CXR infiltrates.
No evidence of volume overload.

Question 32

How is TRALI treated?

Answer 32

Supportive: O2, or mechanical ventilation.

Question 33

What the presentation of transfusion related circulatory overload (TACO)? (7)

Answer 33

Sudden dyspnoea
Orthopnea
Tachycardia
Hypertension
Hyperaemia.
Raised JVP and BP.

Question 34

What are the risk factors for TACO? (3)

Answer 34

Elderly or young.
Compromised left ventricular function.
Increased volume or rate of transfusion.

Question 35

What are the two types of allergic reaction seen from transfusion?

Answer 35

Urticarial rash.

Anaphylaxis.

Question 36

What is a febrile non-haemolytic transfusion reaction?
What is the cause?
Management?

Answer 36

Fever, ± shakes, rigors, increased pulse.
Not life threatening.
Due to accumulation of cytokines during storage.
Discontinue transfusion until wrong blood/infection excluded.